Device with detection by suspended piezoresistive strain gauge comprising a strain amplifier cell

Abstract

A device, with piezoresistive detection comprising at least: a proof body on which an effort to be measured is exerted, means of detecting a strain exerted by the proof body under the action of the effort, comprising at least one suspended piezoresistive strain gauge, a strain amplifier cell comprising at least two rigid arms mechanically linked to each other by at least one link element at the level of a first of their ends, a second end of a first of the two rigid arms being mechanically linked to the proof body, a second end of a second of the two rigid arms being fixed to the substrate, the link element being mechanically linked to a first end of the suspended piezoresistive strain gauge.

1 . A device with piezoresistive detection, comprising at least:
 a proof body on which an effort to be measured is exerted,   means of detecting a strain exerted by the proof body under the action of the effort, comprising at least one suspended piezoresistive strain gauge,   a strain amplifier cell comprising at least two rigid arms mechanically linked to each other by at least one link element at the level of a first of their ends, a second end of a first of the two rigid arms being mechanically linked to the proof body, a second end of a second of the two rigid arms being fixed to a substrate, the link element being mechanically linked to a first end of the suspended piezoresistive strain gauge.   
   
   
       2 . The device according to  claim 1 , wherein the suspended piezoresistive strain gauge comprises a second end fixed to the substrate. 
   
   
       3 . The device according to  claim 1 , wherein the suspended piezoresistive strain gauge comprises at least one suspended beam based on a piezoresistive material. 
   
   
       4 . The device according to  claim 1 , wherein the second end of the first rigid arm is connected to the proof body in the vicinity of an embedment of the proof body to the substrate. 
   
   
       5 . The device according to  claim 1 , wherein the link element mechanically links the two first ends of the two rigid arms comprising at least one pivot link. 
   
   
       6 . The device according to  claim 1 , wherein the link element mechanically links the first ends of the two rigid arms comprising a fixed link with the first end of the suspended piezoresistive strain gauge. 
   
   
       7 . The device according to  claim 6 , wherein each of the first ends of the two rigid arms is mechanically linked to the link element by at least one pivot link. 
   
   
       8 . The device according to  claim 1 , wherein the two rigid arms are symmetrical in relation to a principal axis of the suspended piezoresistive strain gauge. 
   
   
       9 . The device according to  claim 1 , wherein the proof body comprises at least one mobile seismic mass in the plane of the substrate, to which is linked the second end of the first rigid arm. 
   
   
       10 . The device according to  claim 9 , wherein the seismic mass is fixed to the substrate through the intermediary of a hinge. 
   
   
       11 . The device according to  claim 9 , wherein the seismic mass is fixed to the substrate through the intermediary of a guiding arm formed in the seismic mass and embedded in the substrate. 
   
   
       12 . The device according to  claim 1 , wherein the proof body comprises at least one resonant element flexing in the plane of the substrate. 
   
   
       13 . The device according to  claim 12 , wherein the resonant element is of beam or diapason type. 
   
   
       14 . The device according to  claim 12 , further comprising excitation means of the resonant element of capacitive, and/or piezoelectric, and/or magnetic and/or thermoelastic type. 
   
   
       15 . The device according to  claim 12 , wherein two ends of the resonant element are fixed to the substrate. 
   
   
       16 . The device according to  claim 12 , wherein the proof body further comprises at least one mobile seismic mass in the plane of the substrate, linked to the resonant element. 
   
   
       17 . The device according to  claim 16 , wherein the seismic mass is fixed to the substrate through the intermediary of a hinge. 
   
   
       18 . The device according to  claim 16 , wherein the resonant element is linked to the seismic mass in the vicinity of an embedment of the seismic mass to the substrate. 
   
   
       19 . The device according to  claim 1 , wherein the proof body comprises at least two mobile seismic masses in the plane of the substrate, two link arms linked to each of the two seismic masses through the intermediary of flexing arms intended to transmit the movements of the seismic masses to the link arms, the second end of the first rigid arm of the strain amplifier cell being linked to one of the link arms in the vicinity of an embedment of said link arms to the substrate. 
   
   
       20 . The device according to  claim 19 , the link arms and the flexing arms forming a substantially rectangular frame. 
   
   
       21 . The device according to  claim 19 , further comprising excitation means of seismic masses of electrostatic and/or thermal and/or piezoelectric type. 
   
   
       22 . The device according to  claim 1 , further comprising at least one second strain amplifier cell comprising at least two rigid arms mechanically linked to each other by at least one link element at the level of a first of their ends, a second end of a first of the two rigid arms being mechanically linked to the proof body, a second end of a second of the two rigid arms being fixed to the substrate, the link element being mechanically linked to a first end of a second suspended piezoresistive strain gauge intended to work in differential manner in compression or tension in relation to the first suspended piezoresistive strain gauge working respectively in tension or in compression. 
   
   
       23 . The device according to  claim 22 , further comprising at least two resistive elements and a polarisation source forming, with the other elements of the device, a Wheatstone bridge. 
   
   
       24 . The device according to  claim 1 , further comprising means of measuring the variation in the resistance of the suspended piezoresistive strain gauge. 
   
   
       25 . The device according to  claim 1 , the suspended piezoresistive strain gauge(s) being arranged perpendicularly to the axis of the induced effort to be measured.